Subtract values in a matrix

I need really need some help on this,
I have a matrix which has "l" lines and "c" columns. I want to subtract each value in the matrix by the value the first value in the first line of its column, and give me a matrix with those values, with the first values of the first line being "0", and the same amount of lines and columns

Example: m = [2,2,2;3,3,3;4,4,4] the matrix given should be [0,0,0;-1,-1,-1;-2,-2,-2]